DISTANCE DISTRIBUTION OF RADICAL-PARAMAGNETIC ION-PAIRS STUDIED BY THE ELECTRON-SPIN ECHO METHOD - SPATIAL REGULARITIES OF RADICAL DIFFUSION IN GLASSY ALCOHOLS

Applications of the electron spin echo (ESE) technique to determine the distance distribution function for radical-ion pairs stabilized in solids are described. The ESE signal intensity depends on the ion spin-lattice relaxation time T1, thus on temperature, as well as on the function n(r),n(r) can be determined up to a distance of 50 A. At r < 10 - 20 A it is possible to estimate the portion of radicals stabilized at these distances in the vicinity of a paramegnetic ion. The photochemical reaction Fe3+ + R2CH(OH)→Fe2+ +_R2C(OH) + H+ has been studied in glassy methanol and isopropanol. The pair distribution function n(r) has been obtained at 17 < r < 26 A. Its changes induced by radical diffusion have been studied. The portion of radicals stabilized at distance r < 17 A was about 80% for both alcohols. © 1979.